Authorities in Virginia and North Carolina are searching for a convicted sex offender who kidnapped a 7-month-old girl from her mother at knifepoint, police said Monday.

Virginia State Police said Emma Grace Kennedy was taken by her father, 51-year-old Carl Ray Kennedy, at a Kwik Stop in Danville. The gas station is about three hours southwest of Richmond on the North Carolina border.

An Amber Alert has been issued. Police said the infant is believed to be in "extreme danger."

Danville police Lt. Michael Wallace declined to release the name of the girl's 32-year-old mother because the department typically does not identify victims.

Authorities said Carl Kennedy is registered as a sex offender in Asheboro, which is 30 minutes south of Greensboro, North Carolina. He's currently out of jail on a $250,000 bond on a drug distribution charge.

North Carolina's sex offender registry says Kennedy committed the misdemeanor crime of sexual battery. That means he engaged in sexual contact with someone against his or her will or with someone who was mentally disabled or physically incapacitated, according to the state's criminal code.

Asheboro is in Randolph County, where Sheriff's Capt. Bernie Maness said authorities had no information on his whereabouts. He said authorities are checking out tips from people about places he's been seen in the past.

Kennedy is described in the police alert as a white man with gray hair, 5 foot 8 inches, weighing 170 pounds, last seen driving a gold 4-door Suzuki, with the North Carolina tag FAA-1873 or EKZ 5093.

Police said he has tattoos of skulls on his forearms, an eye on the back of his right hand, a pitbull with "american bulldog" written under it on his upper right arm, and a wizard on his upper left arm.